The invention relates to liquid containers and more particularly to liquid containers constructed to allow complete drainage of the container contents thus reducing drainage residue.
The complete drainage of containers has assumed paramount importance. Due to the increasing use of containers as multi-use vessels ever greater amounts of drainage residues are produced, resulting in an unacceptable volume of waste. When a large amount of hazardous waste is involved the volume of waste may assume proportions difficult to manage.
The steps previously taken to solve this problem have not been satisfactory. Attempts have been made to drain residual liquid through the fill and drainage bung of the container by turning the container upside down. In so doing the container had to be moved back and forth to get the residual liquid into the aperture of the bung. It is not possible to obtain an adequate drainage of residues in this manner.
According to a previous design, a container having a specially designed top head has been developed in which the residual liquid is designed to be collected and guided to the bung. For this purpose the central head region has been arched inward, while the outer region adjoining the arched central region slopes obliquely to the wall surface of the container.
When such a container is tipped upside down the residual liquid does indeed collect in the deepest part of the top head, between the arched central region and the outer oblique region and a considerable portion thereof flows through the bung aperture. Even though appreciable improvements have been achieved thereby, additional handling of the container is still required to fully remove the residue.
The problems of drainage of residues is of special importance in the case of drums having two bungs in the head portion of the drum. In this connection, too, according to the previous proposal the central region lying between the bungs has been arched inward, while the outer region adjacent to the arch slopes obliquely to the surface of the drum.
It is an object of the present invention to provide simple means for the optimal drainage of residues from containers while maintaining the stable equilibrium position of a container standing on its head. It is another object of the invention to avoid additional manipulation of the container once it has been inverted, inasmuch as the position of the bung in this orientation can no longer be determined and when the position of the bung is unfavorable, swinging motions are ineffective to assist drainage.